1. Field of the Invention
The field of this invention is measuring devices. Vast multitudes of measuring devices have been created and used through the course of time to measure not only linear dimensions but also non-linear dimensions. Measuring devices allow the user to qualify spatial relationships observed in a two dimensional format. Systems of measurement are based on either the English system with the foot as the base unit of measure or the metric system with the meter as the base unit of measure. The English system is divided into fractional parts and the metric system is divided into decimal portions of the meter.
The present invention relates to a measuring apparatus and methods for measuring and proportioning linear distances, more particularly to tactilely accessible measuring devices for teaching recognition and understanding of units of measure. This device has features designed to facilitate education of beginner measuring device users regarding the concepts of measurement It also has features intended to make acquisition of such skills equally simple for vision-impaired or tactilely oriented learners.
2. Description of the Related Art
Various measuring devices and measuring teaching devices have been used from the start of civilization. Current devices for measurement and teaching measurement vary from a simple graduated ruler to electronic devices capable of extremely accurate measurement. The measuring devices of interest which relate to this invention include devices that allow for feel of the graduations, that can be used to teach beginners how to effectively use a measuring device, and, which facilitate ease of use.
Various rulers have been designed to serve as teaching aids for instruction in units of measure. For example, U.S. Pat. No. 4,614,042 issued Sep. 30, 1986 describes a measuring and instructional ruler for use by persons having learning impairments or physical handicaps. The device has a base panel with one-inch subdivisions delineated by both visual and tactile features. This device also has a top panel which slides on the base panel and has a series of tabs, which are marked in increasing fractions of an inch. The device is used by placing the edge of the base panel on one end of an object to be measured and setting the edge of the sliding top panel against the other end of the object A reading is then taken from the top panel tabs to the subdivisions on the base panel.
Among the limitations of this invention are the following; use for relatively short distances, the embodiment demonstrates only a compact size requiring the user to manipulate thin panels, addresses only fractions of an inch, and its limitation to illustrating the significance of inch and lesser graduations.
U.S. Pat. No. 5,746,001 issued May 5, 1998 discloses a ruler which comprises a teaching aid for instruction in fractional and decimal units of linear measure. It consists of an elongated rectangular body with beveled edges and a central slide. The slide allows a student to determine and verify the fractional portion of a distance measured. Limitations of this patent are; the device only teaches fractional units of measure, cannot respond to distances not allowing lengthwise registration of the device, cannot accomplish center locating or bifurcating functions, and for the flexible embodiment, the assisted reading (labeled graduations) are not direct reading (applied to the observed distance).
Another Patent, U.S. Pat. No. 5,881,469 issued Mar. 16, 1999 discloses a measuring and instructional ruler which is comprised of a base panel with standard units of measure delineated thereon and a transparent sheet with the fractional increments of the same standard units of measure as the base panel. The transparent sheet is positioned over the base panel allowing the student to see the relationship between the unit of measure and the fractional increments thereof. Limitations include; requiring changing to different scales (overlays) to access varying degrees of resolution, only addresses conventional desk-top type ruler applications, and the useful range of graduations must be relocated to the area of interest to number a measurement reading.
Still another, U.S. Pat. No. 6,192,594 B1 describes a ruler that is a triangular shaped prism with three faces and twelve scaled working edges, four located on each prism face. A reference mark from one scale can be interrelated to another scale by turning the prism over to show the new scale in turn allowing a user to learn the interrelationship between fractions, mixed numbers, and decimals. A limitation of this invention is that it addresses unconventional odd common denominators, which can be simulated by applying any conventional ruler obliquely between two parallel demarcations. Its construction of twelve scales over one-half length on each prism face limits the functionality of this device versus a conventional draftsman or architect scale or the device proposed herein; also, this invention has no tactile characteristics. This invention allows the user to learn interrelationships between fractions, decimals, and mixed numbers, based on the English system only.
The Monck patent (U.S. Pat. No. 6,243,959 B1) concerns a ruler device for use in measuring distance and construction of linear objects. It is also used during linear measurement instruction as well as demonstration of the relationship between units of measure and fractional equivalents of these units. Similar to U.S. Pat. No. 5,881,469, this invention consists of a base panel having units of measure and a transparent top panel with fractional increments. The top panel is overlaid on the base panel to demonstrate the relationship between units of measure and fractional equivalents of these units. Limitations for this invention include; the requirement of full discrimination of several colors, the degree of resolution is limited by graduation line width, application to non-distance units such as time, angles, and volumes requires the compilation of a graph, and with regard to compass points or trigonometric functions, it only covers circles to the extent of circular templates the user builds.
The aforementioned patents are focused on a single use as an instructional aid. Still another device, a tactile measuring device, is described in U.S. Pat. No. 6,529,122 B1. This invention utilizes two conductive workpieces, which bear on one another and measure an object through conductivity of a closed cell foam workpiece. This invention does not include visual use and requires an electrical source.
A common shortcoming with all these measuring devices is that each requires the user to have previous knowledge and understanding of the function and use of a ruler. Users must be able to accurately read and comprehend the whole unit and subunit demarcations on a ruler. All the above mentioned patents focus primarily on fractional increments to demonstrate the relationship between such sub-units and the base unit of measure.
In summary, various measuring and instructional ruler devices have been invented that offer functionality for certain applications. However, none of these offer the multitude of uses and teaching aids that the current invention provides.